The largest advertising agency of the world is (A) J. Walter Thompson (B) Saatehi and Saatehi (C) David Ogilvy Inc. (D) MacConn-Erikson Worldwide Correct Ans: (D) Explanation: McCann-Erickson Worldwide holds the title of the largest advertising agency in the world. This agency, part of McCann Worldgroup, has built a reputation for creating iconic global advertising campaigns. It operates in more than 120 countries and serves major brands, including Coca-Cola, Microsoft, and L'Oréal. McCann-Erickson became a leader in advertising by combining creative storytelling with data-driven strategies. The agency specializes in brand building, market research, digital advertising, and media planning. Its innovative campaigns have shaped modern advertising, making it a dominant force in the industry. The other options are also major advertising agencies but are not the largest. J. Walter Thompson (JWT) is one of the oldest agencies but does not surpass McCann-Erickson in size. Saatchi & Saatchi is a creative powerhouse, known for groundbreaking campaigns but is not the biggest. David Ogilvy Inc., now known as Ogilvy, is highly influential but does not hold the top position globally. Thus, McCann-Erickson Worldwide remains the largest advertising agency, leading the industry with its global reach and creative excellence.